Hopes of cash help to pay winter fuel bills were dashed by Gordon Brown last night.

In a speech to business he said he would soon unveil proposals to assist with rising gas and electricity bills - but with no "gimmicks or giveaways".

Instead the measures are expected to focus on helping people get insulation and double-glazing. The Government, locked in talks with the energy firms over the plans, would take "steps to making every home more energy efficient" and cut bills "permanently".

There had been reports ministers would offer a £150 winter fuel allowance to families on child benefit.

But pressure grew yesterday for a windfall tax after it emerged the six big energy firms upped shareholders' dividends to £1,635 - a 19 per cent increase on £1.378billion total in 2006.

Among them Centrica increased its payout to shareholders from £409million to £478 million, and Scottish and Southern Energy from £400million to £474million. E.on, which paid nothing in 2006, £240 million. Scottish Power cut its dividends.

Sir Jeremy Beecham of the Local Government Association said it "torpedoed" energy firm claims a windfall tax would halt investment in generators.

In the speech, to business leaders in Scotland, Mr Brown also slapped down Alistair Darling's warning the economy was the worst for 60 years by insisting Britain faced an "optimistic" future.

He said: "I am cautiously optimistic about the long-term resilience of the economy. At root it is well placed to weather any global economic storm."